IP3-binding polypeptides and methods of using them

Abstract

The present invention provides a high affinity polypeptide having a binding activity to inositol 1,4,5-trisphosphate, to a gene encoding the polypeptide, to a recombinant vector including the gene, to a transformant including the vector and to a method for producing the high affinity polypeptide having a binding activity to inositol 1,4,5-trisphosphate.

What is claimed is: 
     
       1. An isolated polypeptide consisting of the amino acid sequence of position 224 to 604 in SEQ ID NO: 4. 
     
     
       2. An isolated polypeptide consisting of the amino acid sequence of position 224 to 604 in SEQ ID NO: 4, wherein the arginine at position 441 of SEQ ID NO: 4 is replaced with glutamine. 
     
     
       3. An isolated polypeptide consisting of the amino acid sequence of position 1 to 604 in SEQ ID NO: 4. 
     
     
       4. An isolated polypeptide consisting of the amino acid sequence starting at position 224 of SEQ ID NO: 4 and extending to at least position 579 of SEQ ID NO: 4 and at most position 604 of SEQ ID NO: 4. 
     
     
       5. An isolated polypeptide consisting of a glutathione S-transferase and the amino acid sequence of position 224 to 604 in SEQ ID NO: 4. 
     
     
       6. An isolated polypeptide consisting of a glutathione S-transferase and the amino acid sequence of position 224 to 604 in SEQ ID NO: 4, wherein the arginine at position 441 of SEQ ID NO: 4 is replaced with glutamine. 
     
     
       7. An isolated polypeptide consisting of a glutathione S-transferase and the amino acid sequence starting at position 224 of SEQ lID NO: 4 and extending to at least position 579 of SEQ ID NO: 4 and at most position 604 of SEQ lID NO: 4. 
     
     
       8. An inhibitor of an IP3-induced calcium release consisting of the polypeptide of any one of  claims 1  and  2 – 7 . 
     
     
       9. A composition comprising the polypeptide of any one of  claims 1  and  2 – 7  and a pharmaceutically acceptable carrier or additive. 
     
     
       10. An IP3 binding protein as represented by the polypeptide of any one of  claims 1  and  2 – 7 . 
     
     
       11. A method for inhibiting IP3-induced calcium release in a cell expressing an IP3 receptor protein comprising SEQ ID NO:4, the method comprising contacting the cell with the polypeptide of any one of  claims 1  and  2 – 7 .